In the past, the Internet apparatus used two independent wires to transmit data and power, respectively. The combination of Rj-45 connectors and four pairs of twisted pair cables is used to transmit data. However, four pins (4, 5, 7, 8 pin) of the RJ-45 connector and two pairs of the twisted pair cables are idle, because only two pairs of the twisted pair cables are occupied while transmitting data. A new technology called Power over Ethernet (POE), therefore, has been developed to utilize the idle pins. This technology uses the unused pins to transmit power. Such technology obviates need for an additional power supply in an Internet apparatus, because required power can be supplied by a central apparatus in an Internet system. This central apparatus can also be combined with an Uninterruptible Power Supply, UPS, to insure that Internet apparatuses connected to the Internet system can work normally when power fails.
This POE apparatus gradually has become an essential part of a wireless Internet base station. Base stations must be located in higher places to improve signal reception and transmission. In general, such higher places do not provide a power outlet. An additional power arrangement, therefore, is required for providing power to the base station, which increases costs. However, the POE technology can solve this problem. The POE technology can provide flexibility when selecting a base station location.
However, the conventional framework has some problems. For example, if the Internet apparatus are not compatible with the POE specification or requires power that exceeds the central apparatus can supply, the conventional central apparatus fail to work.